NB. Definitions for Software Engineering Chapter

NB. Rational Arithmetic Operations

plus_rat =: dyad def '(((num x.) * den y.) + (num y.) * den x.) make_rat (den x.) * den y.'
minus_rat =: dyad def '(((num x.) * den y.) - (num y.) * den x.) make_rat (den x.) * den y.'
times_rat =: dyad def '((num x.) * num y.) make_rat (den x.) * den y.'
divide_rat =: dyad def '((num x.) * den y.) make_rat (den x.) * num y.'

equal_rat =: dyad def '((num x.) * den y.) = (num y.) * den x.'
print_rat =: monad define
if. 1 = denum =. den y.
  do. format num y.
  else. (format num y.) , '%' , format denum
end.
)

NB. Constructor (Do not remove common factors)

make_rat =: append

NB. Accessors

num =: 0 bond from
den =: 1 bond from

NB. Constructor (Remove common factors at construction time)

make_rat =: dyad def '(x. % g) append y. % g =. x. gcd y.'

NB. Accessors

num =: 0 bond from
den =: 1 bond from

NB. Constructor (Remove common factors at access time)

make_rat =: append

NB. Accessors

num =: monad def 'num % (num =. 0 from y.) gcd 1 from y.'
den =: monad def 'den % (0 from y.) gcd den =. 1 from y.'